Resistance heating system

ABSTRACT

An electric heating system for mounting in floors of building structures includes a pair of spaced tubular manifolds interconnected by a plurality of spaced tubular members positioned between the manifolds and in communication therewith. Each of the manifolds is provided with an electrode extending the length of the manifolds and the electrodes are operatively connected across a voltage source. An electrically conductive liquid of a predetermined electrical resistance fills the manifolds and tubular members and is in contact with the electrodes whereby heating current can be caused to flow through said liquid from one electrode to the other to produce heat. The tubular members are made of plastic material which will melt when exposed to high ambient temperature conditions, thereby causing liquid to drain from the system to shutdown the heating system by open circuiting the electrodes. A liquid reservoir communicates with the system for assuring sufficient liquid supply and for providing space to accomodate thermal expansion of the liquid in the system.

United States Patent [191 Cornella et al.

[ Apr. 30, 1974 1 RESISTANCE HEATING SYSTEM [22] Filed: June 12, 1972 [21] Appl. N0.: 261,680

[52] US. Cl 219/341, 219/213, 219/284,

[51] Int. Cl. H05b 3/60, H010 11/00, F24d 13/04 [58] Field of Search 219/284-295, 219/341, 365, 213; 338/80, 222

664,076 l/l952 Great Britain 219/341 Primary Examiner-A. Bartis 'Attomey, Agent, or Firm-Clarence A. OBrien; Harvey B. Jacobson 157] ABSTRACT An electric heating system for mounting in floors of building-structures includes a pair of spaced tubular manifolds interconnected by a plurality of spaced tubular members positioned between-the manifolds and in communication therewith. Each of the manifolds is provided with an electrode extending the length of the manifolds and the electrodes are operatively connected across a voltage source. An electrically conductive liquid of a predetermined electrical resistance fills the manifolds and tubular members and is in contact with the electrodes whereby heating current can be caused to flow through said liquid from one electrode to the other to produce heat. The tubular members are made of plastic material which will melt when exposed to high ambient temperature conditions, thereby causing liquid to drain from the system to shutdown the heating system by open circuiting the electrodes. A liquid reservoir communicates with the system for assuring sufficient liquid supply and for providing space to accomodate thermal expansion of the liquid in the system.

9 Claims, 4 Drawing Figures SHEEI 2 BF 2 RESISTANCE HEATING SYSTEM The present invention is generally related to heat generating systems and, more particularly, to an improved, low cost, resistance heating system for domestic commercial and industrial applications.

Over the years, various electrical heat generating systems have been proposed. Several such systems utilized electrical power for the purposes of generating steam which in turn, was fed to conventional steam heating assemblies. More recently, radiant electrical heating systems have been proposed but for the most part have proven unacceptable due to low efficiency levels and high operating costs.

It is an object of the present invention to provide an improved electrical heating system which is relatively inexpensive to manufacture and install, yet is substantially maintenance free and economical to operate.

Another object of the present invention is to provide a unique electric resistance heating system which provides heating of the surrounding atmosphere, and the like, by thermal conduction from pipes filled 'with a liquid, or electrolyte, of predetermined electrical resistan- It is a further object of the present invention to provide a versatile electric resistance heating system comprising elongated tubular members of dielectric, nonconductive material filled with a conductive liquid of predetermined resistance, whereby voltage applied to the ends of the tubular members cause current flow through the liquid to generate heat therein.

These together with other objects and advantages which will become subsequently apparent reside in the details of construction and operation as more fully hereinafter described and claimed, reference being had to the accompanying drawings forming a part hereof, wherein like numerals refer to like parts throughout, and in which:

FIG. 1 is a perspective view of the electrical heating system of the present invention installed in a typical building structure.

FIG. 2 is a plan view of a first embodiment of the present invention with sections removed.

FIG. 3 is a sectional view, taken along section 3-3 of FIG. 2.

FIG. 4 is a sectional view of a second embodiment of the present invention.

Referring now, more particularly, to FIG. 1 of the drawings, the electrical heating system of the present invention is generally indicated by the numeral and is illustrated as being mounted in the floor of a typical building structure 12. The system includes a plurality of elongated tubular members 14 and 15 which are mounted beneath floor boards 16 or a similar flooring surface in either a singular or grid like configuration. The system is provided with a thermostatic control 18, preferably of a conventional type, mounted in a wellknown manner to an appropriate electrical system, by way of conductors 20 and 22. Each of the tubular members is filled with a liquid of predetermined electrical characteristics, as hereinafter explained, through which a current is caused to flow, whereby heat is generated and conducted to the surrounding atmosphere and structure. When the temperature within the building structure reaches the pre-selected high setting, the thermostat is effective to deenergize the heating system until a pre-selected low temperature condition exists at which time the system is again energized.

Referring to FIG. 2 of the drawings, a first embodi-- ment of the present invention is illustrated and is generally indicated by the numeral 24. This embodiment of the system is provided with a pair of elongated electrodes 26 and 28 which are connected to the terminals of a voltage source 30, preferably V.A.C. or 220 V.A.C. Current flow to electrode 26 passes through thermostat 32 such that energization of the heating system requires a closure of the thermostat contacts. The electrodes extend through the interior of a pair of elongated pipes or manifolds 34 and 36 filled with a conductive fluid or electrolyte 38 of predetermined electrical resistance. One such appropriate electrolyte is disclosed in U. S. Pat. No. 3,469,079to Cotton, et al. If desired, other appropriate electrolytes, such as salt brine solutions, may be utilized with the system of the present invention. The electrodes 26 and 28 are supported by mounting members 40 and 42 at the opposite ends of the pipes, such that the electrodes extend generally along the axis of the associated pipe and are maintained in intimate contact with the surrounding conductive fluid.

A plurality of tubular members 44 extend transversely between pipes 34 and 36 and are connected thereto such that their interiors communicate with the interiors of the pipes and are substantially filled with the above-mentioned conductive liquid. Each of the tubular members is made of a dielectric, non-conductive material, such as polyethylene or polyvinyl chloride. This assures that there is no current flow directly through the material of the tubular members extending between the electrodes. As current is applied to the electrodes with the thermostat contacts closed, current flow through the liquid in each tubular member is effected. Due to the predetermined resistivity of the conductive liquid, there is a heat dissipation within the liquid which serves to heat the surrounding atmosphere or building structure.

It will be appreciated that most electrolytes have a tendency to expand under increased temperatures. Thus, the system is provided with a liquid accumulator or reservoir 46 in fluid communication with the pipes or tubular members and provided with appropriate venting as indicated at 48 in order to absorb any expansion of the liquid. The preferred structure of the liquid accumulator is best illustrated in FIG. 3, and includes a fill cap 50 threadedly mounted to a cover member 52. The reservoir is mounted above the pipes and tubular members, such that the liquid is free to flow downwardly through the passageway provided by a conventional pipe coupling indicated at 54. The reservoir is partially filled prior'to start up of the system such that there is sufiicient space remaining to absorb an expansion of the liquid in the pipes or tubular members. By providing a reservoir of appropriate size, the full condition of the tubular members may be maintained, and at the same time prevent overflow through the reservoir vent under the highest of temperature conditions.

From the foregoing description of the first embodiment of the present invention, it will be appreciated that heating may be provided by way of a network or gridwork of non-conductive tubular members extending between a pair of generally parallel pipes which serve as mountings for elongated electrodes, whereby the conductive liquid is maintained in intimate contact with the electrodes to provide an electrical ,path through the interior of each tubular member. Of course, it is not intended that the first embodiment be limited to the exact number of tubular members illustrated, or to the parallel arrangement between the tubular members and the respective pipes. Any number of tubular members or pipes may be utilized so long as the size of the network is maintained within feasible limits. In colder climates, it may be advisable to mount the tubular members closer together to provide a greater heat dissipation per unit area of the piping network. The rate of heat dissipation may also be increased by utilizing an electrolyte of lesser effective resistivity, or providing tubular members of greater diameter and cross-section.

With reference to FIG. 4 of the drawings, a second embodiment of the heating system of the present invention is generally indicated by the numeral 55 and includes a single elongated tubular member 56, of nonconductive material, filled with an appropriate conductive liquid 58, such as described above. A pair of conductive electrodes 60 and 62 are mounted at opposite ends of tubular member 56 and are connected to an appropriate voltage source, such as that indicated at 64. The electrodes are supported by mounting collars 66 which are surrounded by sleeve members 68 and 69, respectively, which receive opposite ends of the tubular member 56. Sleeve 69 is provided with a pipe coupling for mounting an accumulator or reservoir 70, as that described above. it will'be appreciated that the second embodiment of the present invention utilizes the same .basic'heating concept of the first embodiment, but is of a much more compact, elongated configuration suitable for installation in narrow passageways, halls, or the like.

From the foregoing descriptions, it will be appreciated that the electrical heating system of the present invention provide a unique means of electricallyheating domestic, commercial and industrial structures at a reasonable cost. The relative over-all simplicity of the heating system renders it economical to manufacture and install. Furthermore, there are no moving parts with the system, other than those which may be associated with the liquid accumulator and, as such, the cost of maintenance is kept to a minimum. It will also be appreciated that the electrical resistance heating system of the present invention is substantially noisefree and does not produce undesirable odors or fumes, as do most conventional heating systems. It should be noted that the electrical heating system utilizes tubular members made from plastic, or similar materials, which are non-conductors of electricity. Such materials have a tendency to soften and deteriorate under high temperatures normally encountered under hazardous fire conditions. This quality of the tubular members provides an additional safety factor to the heating system, as the tubular members will be melted away under the influence of flames to drain the pipes and other tubular members and effect a shut-down of the heating system by open circuiting the electrodes. Furthermore, draining may aid in extinguishing flames within the immediate vicinity.

The foregoing is considered as illustrative only of th principles of the invention. Further, since numerous modifications and changes will readily occur to those skilled in the art,,it is not desired to limit the invention to the exact construction and operation shown and described, and accordingly all suitable modifications and equivalents may be resorted to, falling within the scope of the invention.

What is claimed as new is as follows:

1. An electric heating system for mounting in the floors of building structures, said system comprising a voltage source, first and second elongated pipes in spaced relation to each other, first and second elongated electrodes operatively connected across said voltage source and axially mounted in the interiors of said first and second pipes, respectively, each of said electrodes extending through substantially'the entire length of the associated pipe, a plurality of elongated tubular members of non-conductive, dielectric plastic material externally exposed to ambient conditions, each tubular member being connected at opposite ends thereof to said first and second pipes, respectively, the interior of said tubular members communicating with the interiors of said pipes, and a liquid of predetermined electrical conductivity filling substantially the entire interiors of said pipes and tubular members and being in intimate contact with said electrodes to conduct heating current within each of the tubular members.

2. The system set forth in claim 1, wherein said pipes include mounting members at the opposite ends thereof supporting the ends of said electrodes such that they are in axial orientation relative to the associated pipes.

- 3. The system set forth in claim 2, wherein said system includes a liquid reservoir means communicating with the interior of said pipes and tubular members for assuring sufiicientliquid supply by receiving and dissipating liquid in response to thermal expansion conditions.

4. The system set forth in claim 3, wherein said reservoir means includes a liquid chamber mounted above said pipes and tubular members and being vented to the atmosphere.

5. The system set forth in claim 2, wherein said tubular members and pipes are horizontally mounted in the floor of a building structure.

6. The system set forth in claim 5, wherein said heating system includes thermostat means associated with said voltage source for disconnecting one of said electrodes from said voltage source in response to preselected temperature conditions.

7. The system set forth in claim 6, wherein said system includes a liquid reservoir means communicating with the interior of said pipes and tubular members for assuring sufficient liquid supply by receiving anddissipating in response to thermal expansion conditions.

8. The system set forth in claim 7, wherein said reservoir means includes a liquid chamber mounted above said pipes and tubular members and being vented to the atmosphere.

9. An electric heating system comprising a pair of spaced manifolds, a plurality of non-conductive tubular members horizontally interconnected between said manifolds and in connection therewith, an electrically conductive liquid filling said manifolds and the tubular members, an electrode supported internally in each of said manifolds and extending transversely of said tubular members, and a source of voltage connected across said electrodes for producing heating current through the liquid in each of the manifolds tubular members between the electrodes exposed to each other through the tubular members, said tubular members being made of a plastic material that melts when exposed to high ambient temperature conditions to drain the liquid from the manifold and cause shutdown of the heating system. 

1. An electric heating system for mounting in the floors of building structures, said system comprising a voltage source, first and second elongated pipes in spaced relation to each other, first and second elongated electrodes operatively connected across said voltage source and axially mounted in the interiors of said first and second pipes, respectively, each of said electrodes extending through substantially the entire length of the associated pipe, a plurality of elongated tubular members of non-conductive, dielectric plastic material externally exposed to ambient conditions, each tubular member being connected at opposite ends thereof to said first and second pipes, respectively, the interior of said tubular members communicating with the interiors of said pipes, and a liquid of predetermined electrical conductivity filling substantially the entire interiors of said pipes and tubular members and being in intimate contact with said electrodes to conduct heating current within each of the tubular members.
 2. The system set forth in claim 1, wherein said pipes include mounting members at the opposite ends thereof supporting the ends of said electrodes such that they are in axial orientation relative to the associated pipes.
 3. The system set forth in claim 2, wherein said system includes a liquid reservoir means communicating with the interior of said pipes and tubular members for assuring sufficient liquid supply by receiving and dissipating liquid in response to thermal expansion conditions.
 4. The system set forth in claim 3, wherein said reservoir means includes a liquid chamber mounted above said pipes and tubular members and being vented to the atmosphere.
 5. The system set forth in claim 2, wherein said tubular members and pipes are horizontally mounted in the floor of a building structure.
 6. The system set forth in claim 5, wherein said heating system includes thermostat means associated with said voltage source for disconnecting one of said electrodes from said voltage source in response to preselected temperature conditions.
 7. The system set forth in claim 6, wherein said system includes a liquid reservoir means communicating with the interior of said pipes and tubular members for assuring sufficient liquid supply by receiving and dissipating in response to thermal expansion conditions.
 8. The system set forth in claim 7, wherein said reservoir means includes a liquid chamber mounted above said pipes and tubular members and being vented to the atmosphere.
 9. An electric heating system comprising a pair of spaced manifolds, a plurality of non-conductive tubular members horizontally interconnected between said manifolds and in connection therewith, an electrically conductive liquid filling said manifolds and the tubular members, an electrode supported internally in each of said manifolds and extending transversely of said tubular members, and a source of voltage connected across said electrodes for producing heating current through the liquid in each of the manifolds tubular members between the electrodes exposed to each other through the tubular members, said tubular members being made of a plastic material that melts when exposed to high ambient temperature conditions to drain the liquid from the manifold and cause shutdown of the heating system. 